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Archive for January, 2011

Having recently aquired a TV capable of accessing on-line resources, we thought we’d have a go at using it to watch a film from LoveFilm’s service. We already subscribe to rent DVDs and BluRays from them so a large portion of their library is available to us online as well. We’ve never bothered in the past, as watching a film on the laptop isn’t my idea of fun. But now it’s a few clicks to watch it on our main telly…

It was easy enough to register the TV against our account so that we can pick a film from the on-screen list which is propagated from the ones our account entitles us to access! That required a laptop connection to LoveFilm’s site of course but now that’s done, we can do the rest from the telly.

So we quickly settled on a film to watch and within seconds, we were watching a ten second “test” film which just demonstrates the conneciton is working OK. Then it loads the film and off we go…

… for about half an hour, then it stops and says “Network Down”. It isn’t. Suspecting an online backup running on the office computer might be causing an issue, I go and stop that, whilst Liz re-starts the film and finds where we’d got to. And it’s fine for ten minutes then…

… off it goes again.

Now we live in the sticks and will never get 24mbits broadband which your average council house dweller deems essential and insists should only cost a fiver a month. But we get a pretty good 2mbits, and it almost never goes down. I checked the router recently and it had been online for over a year. And, in fact, we have two such connections to the house with different networks behind them, as it’s essential for the business. So I know we’re not short of bandwidth and that the connection is not dropping.

After twenty minutes more of re-starting the film I finally set the sniffers on it to see what was going on. The “help” on LoveFilm’s website is all aimed at a very low level and the information to solve the problem just isn’t available.

But solve it I did. So lest you find yourself in the same predicament, read on.

As I mentioned, we have a dual WAN connection. We use a Sonicwall firewall which has dual WAN connections, and one DSL link is connected to each port. The system can be st up in a number of ways but we have it set to share the workload out evenly across the two links. Should either link fail, the other will take up the entire load until the first is fixed.

Some services are not happy being “split” like this and the Sonicwall has tools to cope. It also has connection monitoring tools so I was able to work out WHAT the LF service was doing.

LF doesn’t stream the film. Rather, every three or four minutes, it connects to a server and downloads the next segment of the film. I say “a” server because it doesn’t use just one. Each time it connects, it picks one presumably via round-robin DNS or similar. So each “chunk” of the film can, and clearly does, come from a different server. The port used is 443, so there’s no way for the firewall to recognise this access as other than an HTTPS connection. And when the film fails, I see zero bytes returned from the server. So my assumption is that the LF system doesn’t like the request for the next film chunk coming from a different IP address. Rather than logging in each time and confirming I’m still entitled to be accessing the server and asking for a section of the film, it’s just remembering the IP address I came from for the previous segment, and if I appear from a different IP address, it just ignores me. The time taken between the requests, and the fact that the requests are sent to *different* LF servers each time, means that the Sonicwall doesn’t recognise them as part of the same “service”, if it did, it would’ve automatically tried to keep each request on the same WAN port.

So I set the Sonicwall up to allow the TV to use just the first WAN connection, and never to “split” the traffic from the TV over the two networks. Since then, the film has run smoothly!!

I note this operating method doesn’t apply to all services. BBC’s “iPlayer” opens to channels to a server and holds them open whilst the program plays. This would’ve worked fine, as once open the IP connection stays on the same WAN port!

So – in summary – if you have a dual-WAN network and you want to watch films using LoveFilm’s on-line service, you will need to set your load balance system up to connect you via just ONE fixed WAN port. If you don’t know how, speak to the supplier of your load balance equipment. And if you’re trying to watch on your laptop or office computer, you may find your company IT dept are not interested!